﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

   class DiffLetters
    {
        static void Main(string[] args)
        {
            string text = "I was born at 14.06.1980. My sister was born at 3.7.1984. In 5/1999 I graduated my high school. The law says (see section 7.3.12) that we are allowed to do this (section 7.4.2.9).";
            text=text.ToLower();
            int[] counts=new int['z'-'a'+1];

            foreach (char symbol in text)
            {
                if (symbol>='a' && symbol <= 'z')
                {
                    counts[symbol - 'a']++;
                }
            }
            for (int i = 0; i < counts.Length; i++)
            {
                if (counts[i] != 0)
                {
                    Console.WriteLine("{0}: {1}", (char)(i+'a'), counts[i]);
                }
            }
        }
    }

